Interest expenses may be excluded from the calculation of net operating expenses for a fiscal year, if the provider funded a debt service reserve or other interest reserve under requirements imposed by a financial institution or under applicable financing documents, to the extent the reserve fund included amounts to cover interest for that fiscal year. Except as otherwise provided in this part, a provider shall set aside for each facility subject to this subtitle operating reserves that: before January 1, 2023, equal 15% of the facility’s net operating expenses for the most recent fiscal year for which a certified financial statement is available; and beginning January 1, 2023, equal 25% of the facility’s net operating expenses for the most recent fiscal year for which a certified financial statement is available. The provider shall keep the operating reserves in a reasonably liquid form in the judgment of the provider. Beginning January 1, 2014, the assets held by the provider as the operating reserves required under this subsection: except as provided in paragraph (4) of this subsection, shall be unrestricted cash and investments; and may not: be met with a line of credit; or except as provided in paragraph (4) of this subsection, be hypothecated, pledged as collateral, or otherwise encumbered by the provider in any manner. Beginning January 1, 2014, the assets held by the provider as the operating reserves may be encumbered if: the assets are encumbered by contractual obligations undertaken before January 1, 2014, that have not materially changed since January 1, 2014; or the assets are encumbered as part of a general security pledge of assets or similar collateralization that is part of the provider’s long–term capital debt covenants included in the provider’s long–term debt indenture or similar financial instrument but which remain available to the provider to pay operating expenses without substantial restrictions or limitations. A provider shall meet the requirements of subsection (b) of this section within 10 full fiscal years after the date of its initial certificate of registration. A provider shall set aside at least 10% of the reserves required under subsection (b) of this section at the end of each fiscal year after the date of its initial certificate of registration, up to a total of 100% at the end of the 10th fiscal year. The Department may allow a provider to modify the minimum rate required under paragraph (2) of this subsection or extend the time to meet the requirements of subsection (b) of this section if the modification is necessary to maintain the financial viability of the facility.